Optical transceivers are used to transmit and receive optical signals for various applications including, without limitation, internet data center, cable TV broadband, and fiber to the home (FTTH) applications. Optical transceivers provide higher speeds and bandwidth over longer distances, for example, as compared to transmission over copper cables. The desire to provide higher speeds in smaller optical transceiver modules for a lower cost has presented challenges, for example, with respect to thermal management, insertion loss, and manufacturing yield.
Optical transceiver modules generally include one or more transmitter optical subassemblies (TOSAs) for transmitting optical signals. One approach to TOSAs includes coupling a laser diode, lens, and rotator disposed on an optical bench. These types of TOSAs can couple to a CMOS chip and provide emitted laser light at a particular angle into the same. In turn, the CMOS chip can include a gratings coupler for receiving the emitted laser light and launching the same into, for instance, a fiber. This direct-coupling approach may significantly reduce loss and improve coupling efficiency. However, as TOSAs continue to scale the design and manufacture of such direct-coupling TOSA devices raises numerous non-trivial challenges.